To study the clinical manifestations, diagnosis, treatments and TAZ gene mutation of a child with endomyocardial fibroelastosis as the main manifestation of Barth syndrome.

We analyzed the clinical case history of an one-year and seven-month old boy with Barth syndrome, who visited Peking University First Hospital in November 2014.The chief complaint was " intermittent cough and dyspnea, detected endomyocardial fibroelastosis one month ago" . The blood routine and biochemical tests (myocardial enzymes determination, etc.), and cardiovascular function evaluation were performed to the child. The urine organic acids, blood amino acids and acylcarnitine profiles of the child, and genes of the child and his parents were analyzed.

① The child had normal intelligence with physical growth retardation, movement delay and muscle hypotonia. The blood routine showed neutropenia and neutrophil percentage decreased. Echocardiography showed left ventricular hypertrophy, cardiac hypertrophy and cardiac insufficiency. The urine 3-methyl-glutaconic acid was significantly increased of 241.34 mmol/mol of creatinine(normal value was 0-4.2 mmol/mol of creatinine, normal mean value was 1.1 mmol/mol of creatinine), which was 219.4 times of the normal mean value. The blood amino acids profiles was normal. Plasma free carnitine decreased to 13 μmol/L (normal value was 20-60 μmol/L). The TAZ gene test showed that the child presented c. 280 C>T (p.R94C) mutation. and his mother was heterozygous mutation carriers of c. 280 C>T (p.R94C) mutation . ②After oral medication of L-carnitine, vitamin B1, coenzyme Q10, digoxin, metoprolol tartrate, and other supporting treatment, the physical growth and movement improved, urine 3-methyl-glutaconic acid decreased to normal and heart function recovered to normal.

Barth syndrome is a X-link inherited mitochondrial diseases. It is an important cause of cardiomyopathy. Urine organic acids analysis and TAZ gene test contributed a lot to the clinical diagnosis and the treatment.